I have built my pc for around $800 and can easily run Rust on Ultra 1080p with 100+ fps. You have to research and pick your parts carefully, I'm sure you can easily achieve your goal.
I didn't know exactly where to post this, but I thinking if there was a possibility of adding a course server? I know Minigames has course maps, but it would be based solely around kz and course maps with timers and ranking, etc.. ( You could also change Minigames to multigames/ kill maps only so there is no overlap)